Hydraulic motor



Sept. 27, 1966 J, FAlSANDlER 3,274,898

HYDRAULIC MOTOR Filed Dec. 24, 1963 2 Sheets-Sheet 1 T FIG. 1

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Sept. 27, 1966 J. FAISANDIER HYDRAULIC MOTOR 2 Sheets-Sheet 2 Filed Dec. 24, 1963 ig Q w FIG. 2

United States Patent M This invention relates to radial cylinder-type hydraulic motors comprising a cylinder block rotating relative to a multialobed reaction member for effecting reciprocation of pistons when the block is rotated, and a stationary valve plate.

One feature of the above mentioned motors is to provide operation at very low speeds. It is known that in the use of cams having a sinusoidal form, the minimum obtainable speed is a function of the relative value of the losses, in passing the top and bottom dead centers, relative to the output, and various ways have been suggested to improve this relationship. However, limitations are imposed by the fact that for technical reasons a functional play is left between the stationary annular valve plate and the rotary cylinder block.

In a very specific case of radial cylinder-type motors providing one stroke per revolution, arrangements are known in which the contact surface between the rotary cylinder block and the valve plate is a plane surface, the valve plane surface being pressed against the cylinder block surface, this arrangement substantially improves the operation at slow speeds by suppressing the functional play.

This prior art arrangement presents a first disadvantage due to the unbalance which the pressure that is applied to the distributor impart-s to the latter so that an auxiliary means must be used which is susceptible of causing a compensating pressure at a diametrically op posed point; a second disadvantage resides in the fact that the application of the pressure on a distributor, which must be mounted so that it is free or floating, makes it necessary to employ auxiliary means to retain the valve plate rotation, that is to say to prevent it from being taken along or entrained into rotation by the cylinder block.

The employment of such auxiliary distributor retaining means presupposes that the contact surface is exactly perpendicular to the axis of rotation. If there exist any faults or imperfections in the perpendicular relationship due to inexact machining, due to play or to defects in the ball bearings which support the rotary shaft, due to nonhomogeneous dilations or deformations of the metal, the valve plate has a tendency in this case to beat or flutter, thus causing systematic losses.

It is an object of the present invention to apply the above mentioned arrangement in the case of motors providing a plurality of strokes per revolution, more particularly to motors providing a high number of strokes per revolutions, for example four, six, eight or sixteen strokes per revolution, while the known structure of this type of motor seem not to have provided more than two strokes per revolution, and to create a motor which does not require any guide arrangement of the distributor by auxiliary means nor a compensating pressure.

On the other hand in the multicylinder motors having multiple strokes and particularly in the motors of this type operating at very low speeds, it becomes imperative to suppress in an absolute manner the losses along the valve plate surface which tend to assume exaggerated values at the moment when the distribution is interrupted.

According to the present invention, one may employ 3,274,898 Patented Sept. 27, 1966 for the cam surfaces which produce the movement of the pistons in the cylinders, forms which are not clearly sinusoidal but which, on the contrary, cause an interruption in the movement of the pistons thus causing an interruption in the distribution so as to create a rotation angle of considerable magnitude in the course of which the distribution by means of the distributor is interrupted at the moment where the reversal between the input and the discharge of the same cylinder takes place.

This'constitutes an essential difference with respect to the multicylinder motors which have only one or at the most two strokes per revolution and whose cam surfaces are of necessity not sinusoidal.

It is an object of the present invention to improve the known arrangement mentioned above, and for this purpose it provides a combination of means which are known in themselves but which combine with each other to provide a perfect distribution even for extremely low speeds of rotation.

Other features and advantages of the present invention will appear from the following description taken in combination with the accompanying drawings in which:

FIG. 1 is a partial axial section of a motor according to the invention in which a rectangular space has been left blank for the distributor which is shown on a larger scale in FIGURE 2, and

FIG. 3 is a partial view of the face of the valve plate viewed from the left in FIGURE 2. taken along section line 3-3 in FIGURE 2.

FIGURE 4 is a partial sectional view taken along section line 4-4 in FIGURE 1.

The embodiment disclosed here for the purpose of explaining the invention is not intended to limit the generic scope to the details and to the specific elements of this embodiment shown only for purposes of illustration.

Referring to FIGURE 1, the stationary housing is designated by numeral 1 and in this housing shaft 2 is mounted for rotation and supported by ball bearings 3 and 4. The motor block 5 is mounted on shaft 2 and rotates with it.

In the cylinder block of this example eleven cylinders such as cylinder 6 are arranged and contain each a piston such as piston 7. The piston 7 carries a roller 10 which rolls on a cam surface 8 of general sinusoidal form if developed. The motor is designed for eight strokes per revolution so that the profile of the cam 33 has eight complete sinusoids, preferably deformed to present flatness at the moment of reversal. Numeral 11 designates the conduit through which the fluid is fed, and numeral 12 the conduit through which it is returned to the supply source. The arrangement mentioned so far is fully known so that its description as well as its illustration need not be made in great detail.

The distributor device comprises the following elements: The hydraulic fluid is supplied to the base of cylinder 6 through conduit 13 located in the rotating part. The valve plate is generally designated by numeral 14. This valve plate has a cylindrical cavity in which is partially engaged a cylindrical piston 15 which is pressed towards the bottom of said cavity by a spring 16 which tends to press it toward the left, as seen in FIGURE 2. The pressure which arrives through conduit 11 acts on the face 17 of the piston. For this purpose the right hand side of piston 15 is lodged in a bore provided in member 18 which is integral with the fixed part.

The piston 15 is traversed by an opening 19 of circular cross-section while a corresponding passage 20 which is located in the valve plate has an elongate cross-section. These two cross-sections are shown in FIGURE 3 in which the piston 15 is indicated in dotted line. In this figure only two pistons are shown, it being understood that the sixteen pistons 15 and their associated valve plate parts, that is two per cam lobe, are divided over the entire circumference, one valve plate part serving for the supply and the next one for the discharge.

The conduit 13 is provided in a part 21 which is connected to the cylinder block and rotates with it. This part 21 presents plane faces 22 and 23, which are perpendicular to the axis .of shaft 2. The part 21 may be integral with the cylinder block or be connected thereto. Valve plate 14 presents confronting plane surfaces 24, 25 which are urged either by means of spring 16 or by the cumulative effect of this spring and by the pressure which arrives through conduit 11 against the corresponding face of part 21.

The valve plate comprises supplemental surfaces 26, 27 designed to balance the difference between the force exercised by the auxiliary pistons toward the left as seen in FIGURE 2, and the force produced by the pressure which acts against surface 24 to 27 of the valve plate 14.

As seen best in FIGURE 3 this supplemental surface is formed by a series of curved sections separated by radial grooves such as 2829 which communicate with peripheral throats 30 and 31. The operation is as follows:

The pressurized fluid arriving through conduit 11 drives piston 15 to the left into the bottom of the bore and the piston in turn pushes the valve plate 14 which thereupon applies pressure against the corresponding face of part 21. At the moment where the distribution takes place the bore 13 is opposite passages 19 and For the cylinder 6 the supply will take place through the conduit 11 and the delivery takes place through conduit 12.

This arrangement permits a reversing of the direction of movement and in this case the supply takes place through conduit 12 and the delivery through conduit 11. It will be seen that the valve plate 14 is prevented from rotating by piston 15 which itself is maintained in place by member 18. In order that the valve plate 14 may carry out a slight floating movement as mentioned above,

it must be fully floating .and be maintained in position.

only by means of the pistons.

The auxiliary pistons 15 are arranged in their bore with a play and they provide the following functions:

(1) They urge the valve plate against the rotating part in an exactly rectilinear direction.

(2) They assure the internal communication for the passage of the oil.

(3) They prevent rotation of the valve plate without necessitating auxiliary immobilizing devices.

(4) They furnish the degree of freedom necessary to permit the valve plate to be in constant contact with the rotating part.

While a preferred embodiment has been shown and described, various modifications and substitutions may be made without deviating from the scope and spirit of this invention. Thus this invention is described by way of illustration rather than limitation and accordingly it is 4 understood that this invention is to be limited only by the appended claims taken in view of the prior art.

What is claimed is:

1. A hydraulic motor comprising in combination a stator,

a rot-or mounted in said stator for rotation about an axis of rotation,

a plurality of cylinders disposed in radial arrangement in said rotor,

piston members received in said cylinders,

a reaction member having a surface in said stator for controlling the movement of said piston members in said cylinders, said surface being multi-lobed to im pose on said pistons upon rotation of said rotor at least three strokes per revolution,

said rotor comprising a flat valve seat surface disposed perpendicularly to said axial rotation,

an annular valve plate having a flat surface for making contact with said flat surface of said rotor during rotation of said rotor,

a conduit in the rotor for each cylinder discharging at one end into one of the cylinders and at the other end through an orifice of said distributor surface of said rotor and having at least one rectilinear portion in the immediate vicinity of said distributor surface of said rotor,

said valve plate being disposed in a floating manner and having an .axis perpendicular to the flat surface of said stator having orifices arranged to sequentially communicate with the orifices of said conduit during rotation of said rotor, a plurality of piston members in said valve plate, each having an axial bore and being engaged partly in a corresponding cavity of the valve plate and partly in a corresponding cavity of the stator, a spring in said cavity of the stator hearing at one end on said piston member and at the other end on said stator, for pressing said valve plate in the direction of said flat surface of the rotor.

2. The motor according to claim 1 wherein the valve plate presents on the side facing the rotor complementary surfaces for balancing the difference between the force exerted by said spring and the hydraulic pressure exerted on the fiat contact surface of the valve plate.

References Cited by the Examiner UNITED STATES PATENTS 2,397,314 3/1946 Grosser 103-161 2,406,138 8/1946 Ferris et al 103-161 2,525,498 10/1950 Naylor et al 103161 2,608,934 9/1952 Ferris 10316l 3,037,489 6/ 1962 Douglas 91-176 MARTIN P. SCHWADRON, Primary Examiner.

FRED E. ENGELTHALER, SAMUEL LEVINE,

Examiners.

P. E. MASLOUSKY, Assistant Examiner. 

1. A HYDRAULIC MOTOR COMPRISING IN COMBINATION A STATOR, A ROTOR MOUNTED IN SAID STATOR FOR ROTATION ABOUT AN AXIS OF ROTATION, A PLURALITY OF CYLINDERS DISPOSED IN RADIAL ARRANGEMENT IN SAID ROTOR, PISTON MEMBERS RECEIVED IN SAID CYLINDERS, A REACTION MEMBER HAVING A SURFACE IN SAID STATOR FOR CONTROLLING THE MOVEMENT OF SAID PISTON MEMBERS IN SAID CYLINDERS, SAID SURFACES BEING MULTI-LOBED TO IMPOSE ON SAID PISTONS UPON ROTATIONS OF SAID ROTOR AT LEAST THREE STROKES PER REVOLUTION, SAID ROTOR COMPRISING A FLAT VALVE SEAT SURFACE DISPOSED PERPENDICULARLY TO SAID AXIAL ROTATION, AN ANNULAR VALVE PLATE HAVING A FLAT SURFACE FOR MAKING CONTACT WITH SAID FLAT SURFACE OF SAID ROTOR DURING ROTATION OF SAID ROTOR, A CONDUIT IN THE ROTOR FOR EACH CYLINDER DISCHARGING AT ONE END INTO ONE OF THE CYLINDERS AND AT THE OTHER END THROUGH AN ORIFICE OF SAID DISTRIBUTOR SURFACE OF SAID ROTOR AND HAVING AT LEAST ONE RECTILINEAR PORTION IN THE IMMEDIATE VICINITY OF SAID DISTRIBUTOR SURFACE OF SAID ROTOR, 